将组转换为数组的连接 javascript

Posted 2023-02-22

【中文标题】将组转换为数组的连接 javascript

【英文标题】：Turn groups into concat of arrays javascript

【发布时间】：2018-09-02 12:28:03

【问题描述】：

我已经设法根据键值将数组拆分为不同的组。我想要实现的是将这些或多或少的组变成一​​个数组，所以我的组变成[[Regio__c],[Categorie__c]]而不是Regio__c:[],Categorie__c:[]。这与普通的 javascript 没有库。

我试过了：return [key].concat.split; 这返回 undefined。

下面是我在 sn-p 中的代码

var filter = [
    "Id": "120",
    "arrayPicklist": "Categorie__c"
  , 
    "Id": "121",
    "arrayPicklist": "Regio__c"
  ,
  
    "Id": "122",
    "arrayPicklist": "Categorie__c"
  , 
    "Id": "123",
    "arrayPicklist": "Regio__c"
  ,
  
    "Id": "121",
    "arrayPicklist": "Regio__c"
  
]


function splitArrayByValue(arr, key) 
  var split = ;
  for (var i = 0; i < arr.length; i++) 
    var p = arr[i][key];
    if (!split[p]) 
      split[p] = [];
    
    split[p].push(arr[i])
  
  return split;



var buckets2 = splitArrayByValue(filter, 'arrayPicklist');

console.log(buckets2);

【参考方案1】：

您快到了，您需要获取值。另一种方法是使用函数Object.values

var filter = [    "Id": "120",    "arrayPicklist": "Categorie__c"  ,     "Id": "121",    "arrayPicklist": "Regio__c"  ,      "Id": "122",    "arrayPicklist": "Categorie__c"  ,     "Id": "123",    "arrayPicklist": "Regio__c"  ,      "Id": "121",    "arrayPicklist": "Regio__c"  ]

function splitArrayByValue(arr, key) 
  var split = ;
  for (var i = 0; i < arr.length; i++) 
    var p = arr[i][key];
    if (!split[p]) 
      split[p] = [];
    
    split[p].push(arr[i])
  
  return Object.values(split);



var buckets2 = splitArrayByValue(filter, 'arrayPicklist');

console.log(buckets2);

您可以使用函数reduce 进行分组，然后使用函数Object.values 来获得所需的输出。

var filter = ["Id":"120","arrayPicklist":"Categorie__c","Id":"121","arrayPicklist":"Regio__c","Id":"122","arrayPicklist":"Categorie__c","Id":"123","arrayPicklist":"Regio__c","Id":"121","arrayPicklist":"Regio__c"];

var result = Object.values(filter.reduce((a, Id, arrayPicklist) => 
  (a[arrayPicklist] || (a[arrayPicklist] = [])).push(Id, arrayPicklist);      
  return a;
, ));

console.log(result);

.as-console-wrapper  max-height: 100% !important; top: 0; 

【参考方案2】：

只需在 splitArrayByValue 函数中返回 Object.values(split) 而不是 split。

var filter = ["Id":"120","arrayPicklist":
"Categorie__c","Id":"121","arrayPicklist":"Regio__c",
"Id":"122","arrayPicklist":"Categorie__c","Id":"123","arrayPicklist":"Regio__c",
"Id":"121","arrayPicklist":"Regio__c"]


function splitArrayByValue(arr, key) 
  var split = ;
  for (var i=0; i<arr.length; i++) 
    var p = arr[i][key];
    if (!split[p])  split[p] = []; 
    split[p].push(arr[i])
  
  return Object.values(split);//<---- just return Object.values(split) instead of split 



var buckets2 = splitArrayByValue(filter,'arrayPicklist');

console.log(buckets2);

【参考方案3】：

你可以使用.reduce():

let data = [
  "Id":"120", "arrayPicklist":"Categorie__c",
  "Id":"121", "arrayPicklist":"Regio__c",
  "Id":"122", "arrayPicklist":"Categorie__c",
  "Id":"123", "arrayPicklist":"Regio__c",
  "Id":"121", "arrayPicklist":"Regio__c"
];

let keys = [...new Set(data.map((arrayPicklist) => arrayPicklist))];

/* 
 * let keys = ["Categorie__c", "Regio__c"];
 * In case you wants to use hard code values
 */

let result = data.reduce((r, c) => (
    r[keys.indexOf(c["arrayPicklist"])].push(c), r
), [[], []]);

console.log(result);

.as-console-wrapper  max-height: 100% !important; top: 0; 

有用的资源：

Array.prototype.reduce() Arrow Functions Comma Operator

【参考方案4】：

制作一组所有可能的类别 (arrayPicklist)。对于这个集合中的每个值，过滤数组并创建一个组：

var array = [
    "Id": "120", "arrayPicklist": "Categorie__c",
    "Id": "121", "arrayPicklist": "Regio__c",
    "Id": "122", "arrayPicklist": "Categorie__c",
    "Id": "123", "arrayPicklist": "Regio__c",
    "Id": "121", "arrayPicklist": "Regio__c"
]

let groups = [...new Set(array.map(x => x.arrayPicklist))]
    .map(p => array.filter(x => x.arrayPicklist === p));

console.log(groups)

也就是说，您真的应该考虑使用库。精心设计和经过良好测试的工具总是优于任何可以想出的 javascript 内置插件的脆弱临时组合。有了lodash，你的问题就一行解决了：

let groups = _.values(_.groupBy(array, 'arrayPicklist'))

就像Ramda：

let groups  = R.values(R.groupBy(x => x.arrayPicklist, array))

【讨论】：

+1。看到你的回答后，我有点纳闷，因为这问题并没有我想象的那么复杂。

【参考方案5】：

如果我理解正确，您希望将对象的值作为数组获取。您可以使用以下方法实现此目的：

1. Object.values:

当你从splitArrayByValue返回时，返回这个：

return Object.values(split);

代替：

return split;

Object.values 仅在 ECMAScript 2017 中有效。如果您使用的是旧版 ECMA，则使用第二种方法，它可以达到相同的效果

2。 Object.keys & Array#map:

如上，不是直接返回split，而是返回这个：

return Object.keys(split).map(function(key) 
  return split[key];
);

使用箭头函数或更短：

return Object.keys(split).map(key => split[key]);

注意：上述两种方法都没有指定子数组的顺序。它可以是任何东西。可能是 [[Regio__c], [Categorie__c]]，也可能是 [[Categorie__c], [Regio__c]]，因为 javascript 中的对象不保留其键值对的顺序。

【参考方案6】：

我了解您希望得到一个二维数组，其中第一级表示 arrayPicklist 值。如果这是正确的，您可以使用 map 和 Set 来实现您想要的，例如

var filter = ["Id":"120","arrayPicklist":
"Categorie__c","Id":"121","arrayPicklist":"Regio__c",
"Id":"122","arrayPicklist":"Categorie__c","Id":"123","arrayPicklist":"Regio__c",
"Id":"121","arrayPicklist":"Regio__c"]


function splitArrayByValue(arr, key) 
  let keys = arr.map(entry => 
    return entry[key];
  );

  let unique = [...new Set(keys.concat())]; 

  let split = new Array(unique.length);
  for (var i = 0; i < arr.length; i++) 
    let p = arr[i][key];
    let index = unique.indexOf(p);

    if (!split[index]) split[index] = [];
    split[index].push(arr[i])
  
  return split;



var buckets2 = splitArrayByValue(filter,'Id');

console.log(buckets2);